Birds and Horses and Cats, Oh My!

Instructional Guide

Learners will explore the different digestive systems of birds, horses and cats. The lesson will include a short storybook of the digestive system of these animals followed by a short assessment.

Intended Grade Level

This lesson is intended for 9th- 12th graders. Students should be familiar with general anatomy of the GI system, so that they are able to appreciate the differences between these species.

Learning objectives

• Understand the movement of food through the digestive systems of birds, horses, and cats.
• Understand the basic functions of each component of the digestive system
• Compare and contrast the digestive systems of birds, horses, and cats. Explain why these differences and similarities exist.

Lesson Format

Student page

This can be done in any size group. The material and activities require a computer and internet access.

• First students will work through a storybook style lesson about birds, horses and cats (40 minutes)
  • each section will include a short reading, an image to explore to learn about the GI system of the animal, and a short-answer knowledge check
• Next, will work on the assessment, which is a short quiz reflecting the material learned in this lesson (10 minutes)

Lesson Background

Birds have a unique digestive process. Food passes from the beak into the crop (a storage pouch), then to the proventriculus (glandular stomach) where enzymatic digestion begins, and into the gizzard (muscular stomach) for mechanical breakdown. From there, it continues through the intestines to the cloaca.

Horses are non-ruminant herbivores (hindgut fermenters). Food moves from the mouth to the stomach, then into the small intestine for enzymatic digestion. The large cecum and colon play a major role in microbial fermentation of fibrous plant material.

Cats are obligate carnivores with simple, monogastric stomachs. Food moves from the mouth to a relatively short digestive tract optimized for rapid digestion and absorption of animal protein and fat, with little need for fermentation.

The chart below serves as a good comparison tool between these three species:

Activities

While working through the lesson, students will have opportunities to work through activities for each animal. Each animal will have an image to explore to learn about their GI system, prompting students to click on the image to learn. Then students will have the chance to go through a “knowledge check” where they can type in answers to three prompts about the material they just learned.

Common misconceptions and challenge points

• Some may think a longer gut always means more efficient digestion. But digestive efficiency depends on diet type and the presence of specialized organs, not just length.
• Students may be confused as it is generally conceived notion that the stomach is the most important part of the digestive tract. Students may not understand that fermentation and nutrient absorption occur primarily in the hindgut for horses, and multiple compartments play major roles in birds.
• Birds excrete both solid and liquid waste through the cloaca, which combines digestive and urinary functions. Students may not realize this is very different from mammals.

Assessment

Students will answer a short quiz that includes multiple choice, true/false, and fill in the blank style questions reflecting what they have learned throughout the lesson.

Further exploration

Other chapters that may be interesting within this textbook may be beneficial and are linked below:

Fore stomach, true stomach, red stomach, blue stomach

Multiple GI Tracts? Jeez!